Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/30—Sulfur-, selenium- or tellurium-containing compounds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/04—Oxygen-containing compounds
  • C08K5/09—Carboxylic acids; Metal salts thereof; Anhydrides thereof
  • C08K5/098—Metal salts of carboxylic acids
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K21/00—Fireproofing materials
  • C09K21/02—Inorganic materials

Definitions

• the present invention relates to a flame retardant and a process for producing the same.
• the present invention is concerned with a flame retardant comprising ammonium sulfate as an effective component and a process for producing the same.
• ammonium sulfate is useful as a flame retardant for a flammable polymer.
• Ammonium sulfate however, has drawbacks such as strong self-agglomeration (caking or integrity), difficulty in conducting pulverization and the occurrence of agglomeration during storage even where it is pulverized.
• a synthetic resin such as a thermoplastic resin or a thermosetting resin
• agglomeration occurs due to the shearing caused at the time of mixing.
• ammonium sulfate is easily soluble in water, a molded article of a resin containing ammonium sulfate has a water resistance problem.
• ammonium sulfate when the resin composition or an article produced by molding the resin composition is brought into contact with an aqueous substance, ammonium sulfate is eluted, which causes the properties of this composition or the state of the molded article to change, so that useability becomes poor. Further, when this composition is used under highly humid conditions, ammonium sulfate is dissolved and oozed out by moisture contained therein in the case of the occurrence of moisture in the air, etc., so that practical problems, such as the deposition of an ammonium sulfate crystal on the surface of the resin occur. For this reason, although ammonium sulfate is useful as a flame retardant, the use of ammonium sulfate in synthetic resins such as thermoplastic resins or thermosetting resins is very limited.
• Japanese Unexamined Patent Publication (Kokai) No. 63-202639 describes the use of magnesium steatite as a pulverization assistant at the time of the pulverization of ammonium sulfate. This method, however, has problems such as the generation of an ammonia gas during pulverization and coloring of the resin during kneading. Further, Japanese Unexamined Patent Publication (Kokai) No. 60-26046 discloses that dispersion and fluidity can be improved by using a method of improving the self-agglomeration of ammonium sulfate that comprises treating the surface of ammonium sulfate with sodium stearate and sodium laurylsulfonate.
• Japanese Unexamined Patent Publication (Kokai) No. 59-191746 and Japanese Unexamined Patent Publication (Kokai) No. 60-6740 propose a treatment of ammonium sulfate with polysiloxane for the purpose of improving water resistance. According to this method, although an improvement in water resistance can be attained, the process is troublesome.
• the present inventors have made extensive and intensive studies with a view to attaining the pulverization of ammonium sulfate and, at the same time, an alleviation of self-agglomeration, an improvement in water resistance and the prevention of coloration of the resin during kneading, which has led to the completion of the present invention.
• an object of the present invention is to provide a flame retardant comprising ammonium sulfate as an effective component, which is in a pulverised form and has a low level of self-agglomeration, high water resistance and a less liability to coloration of the resin during kneading, and to provide a process for producing the same.
• the present invention provides a finely divided flame retardant comprising a finely divided powder comprised of ammonium sulfate and 0.1 to 10.0 % by weight, based on the weight of ammonium sulfate, of at least one fatty acid salt of aluminum.
• This flame retardant is produced by a process according to the present invention, comprising pulverizing ammonium sulfate in the presence of 0.1 to 10.0 % by weight, based on the weight of ammonium sulfate, of at least one fatty acid salt of aluminum.
• the fatty acid salt of aluminum used in the present invention is preferably an aluminum salt of a saturated or unsaturated fatty acid having 6 to 22 carbon atoms in the fatty acid group.
• Preferred examples of the fatty acid salt include a monofatty acid aluminum salt, a difatty acid aluminum salt and a trifatty acid aluminum salt.
• the amount of the fatty acid aluminum salt is 0.1 to 10.0 % by weight, preferably 0.3 to 5.0 % by weight, more preferably 0.5 to 3.0 % by weight, based on the weight of ammonium sulfate.
• this amount is less than 0.1 % by weight, prevention of self-agglomeration of pulverized ammonium sulfate and prevention of the coloration of a molded article containing ammonium sulfate added thereto are unsatisfactory.
• the use of a fatty acid aluminum salt in an amount exceeding 10 % by weight has an adverse effect on pulverization and flame retardancy.
• Examples of the means for pulverization include a method wherein use is made of a pulverizer.
• ammonium sulfate is pulverized by means of a pulverizer in the presence of at least one fatty acid aluminum salt, so that ammonium sulfate becomes a finely divided powder comprising a particle preferably having a maximum diameter of 75 ⁇ m or less and, at the same time, the surface of the ammonium sulfate particle is treated with the fatty acid aluminum salt.
• a conventional wet or dry type pulverizer can be used for the pulverization, it is preferable to use a pulverizer having a grinding effect, and there is no particular limitation on the solvent used in the case of wet pulverization as long as the solvent, other than water, is inert.
• the solvent other than water
• alcohols such as methanol and ethanol
• hydrocarbons such as n-heptane
• aromatic solvents such as benzene, toluene and xylene are preferable from the viewpoint of easy handleability and drying ease.
• the amount of use of the solvent may vary depending upon the specific gravity of the solvent and the type of pulverizer, it is preferably 1 to 10 times by weight, and preferably 1.5 to 5 times by weight that of ammonium sulfate.
• the solid matter is preferably collected by filtration or centrifuging according to a conventional method and dried under reduced pressure. There is no particular limitation on the particle diameter of ammonium sulfate used in the pulverization.
• thermoplastic resins for example, polyolefin resins such as polypropylene and polyethylene, polyvinyl resins such as polystyrene, polymethyl methacrylate, polyvinyl acetate and polyvinyl alcohol, ethylene-vinyl acetate copolymer, polyamide resins such as nylon, polyester resins such as polyethylene terephthalate and polycarbonate, polyacrylonitrile resins such as ABS resin and AS resin and polyether resins, mixtures and copolymers of the above-described resins and various resins produced by modifying the above-described resins, elastic polymers such as SBR, NBR, polybutadiene and polyisoprene and thermosetting resins such as phenolic resin, unsaturated polyester resin, polyurethane resin and epoxy resin.
• thermoplastic resins for example, polyolefin resins such as polypropylene and polyethylene, polyvinyl resins such as polystyrene, polymethyl methacrylate, polyvinyl a
• pulverization assistants commonly used in the art, for example, titanium oxide and fatty acids.
• the flame retardant according to the present invention does not give rise to agglomeration during storage, and can be homogeneously dispersed in the resin to provide a molded article having excellent water resistance and flame retardancy when it is incorporated and kneaded with the resin, and does not color the resin during kneading.
• the maximum particle diameter and the mean particle diameter were measured by means of a centrifugal automatic particle size distribution measuring apparatus (model CAPA-700 manufactured by Horiba, Ltd.).
• One liter of the flame retardant was placed in a container having a bottom area of 200 cm2 (10 cm x 20 cm), and the surface of the flame retardant was leveled. A load of 200 g/cm2 was applied on the flame retardant, and the number of days taken for the flame retardant to agglomerate was observed.
• the molded article was subjected to through-view ( thickness: 1/16 in.), and the dispersion was judged based on whether or not a coarse agglomerate is present.
• the coloration of the molded article was evaluated with the naked eye immediately after molding.
• Flame retardancy was measured according to UL-94 (thickness of test piece: 1/16 in. for PP and 1/8 in. for other resins) and JIS K 7201 (LOI).
• test piece having a length of 2.5 in., a width of 0.5 in. and a thickness of 1/8 in. was dried in an oven of 50°C for 24 hr, allowed to cool in a desiccator of 23°C for 3 hr and then weighed (A).
• the test piece was immersed in pure water of 23°C for 168 hr, water droplets on the test piece were wiped off with a dry cloth, and the test piece was then immediately weighed (B). This test was conducted on three test pieces, and water absorption was determined by the following equation:
• the resultant flame retardant powder had a maximum particle diameter of 50 ⁇ m and a mean particle diameter of 19 ⁇ m and was free from caking.
• This flame retardant was mixed with a resin in an amount ratio specified in Tables 2 to 6; the mixture was subjected to melt mixing by means of a kneader (manufactured by Irie Shokai Co., Ltd.), and a test piece was molded from the mixture by means of a press molding machine of 200°C (manufactured by Shinto Kinzoku K.K.).
• Example 1 499.5 g of ammonium sulfate and 0.5 g of aluminum dicaproate were previously mixed with each other, and a flame retardant powder was prepared therefrom in the same manner as that of Example 1.
• the resultant flame retardant powder had a maximum particle diameter of 44 ⁇ m and a mean particle diameter of 15 ⁇ m and was free from caking.
• This flame retardant was used according to the formulation specified in Table 2, and a test piece was molded therefrom in the same manner as that of Example 1. The results are given in Tables 1 and 2.
• Example 1 450 g of ammonium sulfate and 50 9 of aluminum trimyristate were previously mixed with each other, and a flame retardant powder was prepared therefrom in the same manner as that of Example 1.
• the resultant flame retardant powder had a maximum particle diameter of 46 ⁇ m and a mean particle diameter of 16 ⁇ m and was free from caking.
• This flame retardant was used according to the formulation specified in Table 2, and a test piece was molded therefrom in the same manner as that of Example 1. The results are given in Tables 1 and 2.
• Example 1 490 g of ammonium sulfate and 10 g of aluminum tristearate were previously mixed with each other, and a flame retardant powder was prepared therefrom in the same manner as that of Example 1.
• the resultant flame retardant powder had a maximum particle diameter of 40 ⁇ m and a mean particle diameter of 12 ⁇ m and was free from caking.
• This flame retardant was used according to the formulations specified in Tables 2 to 6, and test pieces were molded therefrom in the same manner as that of Example 1. The results are given in Tables 1 to 6.
• Example 1 460 g of ammonium sulfate and 40 g of aluminum monobehenate were previously mixed with each other, and a flame retardant powder was prepared therefrom in the same manner as that of Example 1.
• the resultant flame retardant powder had a maximum particle diameter of 48 ⁇ m and a mean particle diameter of 16 ⁇ m and was free from caking.
• This flame retardant was used according to the formulations specified in Tables 2 to 6, and test pieces were molded therefrom in the same manner as that of Example 1. The results are given in Tables 1 to 6.
• a flame retardant powder was prepared in the same manner as that of Example 1, except that silicic anhydride was used instead of aluminum monocaproate.
• the resultant flame retardant powder had a maximum particle diameter of 48 ⁇ m and a mean particle diameter of 18 ⁇ m. However, this flame retardant powder immediately gave rise to caking.
• Test pieces were molded therefrom according to the formulations specified in Tables 2 to 6 in the same manner as that of Example 1. In this case, as opposed to the results of Example 1, the flame retardant gave rise to agglomeration, so that a molded article in which the flame retardant was homogeneously dispersed could not be obtained. Further, the molded articles were colored. The results are given in Tables 1 to 6.
• a flame retardant powder was prepared in the same manner as that of Example 6, except that silicic anhydride was used instead of aluminum tristearate.
• the resultant flame retardant powder was passed through a 200-mesh standard sieve (JIS) to remove coarse particles having a size of 75 ⁇ m or more (1.0 % or less). The mean particle diameter was 14 ⁇ m. In this case, however, caking immediately occurred.
• Test pieces were prepared according to the formulations specified in Tables 2 to 6 in the same manner as that of Example 6. In this case, as opposed to the results of Example 6, the flame retardant gave rise to agglomeration, so that a molded article in which the flame retardant was homogeneously dispersed could not be obtained. Further, the molded articles were colored. The results are given in Tables 1 to 6.
• a flame retardant powder was prepared in the same manner as that of Example 7, except that silicic anhydride was used instead of aluminum tristearate.
• the resultant flame retardant powder was passed through a 200-mesh standard sieve (JIS) to remove coarse particles having a size of 75 ⁇ m (1.0 % or less). The mean particle diameter was 14 ⁇ m. However, caking immediately occurred.
• Test pieces were molded therefrom according to the formulations specified in Tables 2 to 6 in the same manner as that of Example 7. In this case, as opposed to the results of Example 7, the flame retardant gave rise to agglomeration, so that a molded article in which the flame retardant was homogeneously dispersed could not be obtained. Further, the molded articles were colored. The results are given in Tables 1 to 6.
• a flame retardant powder was prepared in the same manner as that of Example 6, except that magnesium stearate was used instead of aluminum tristearate. In this case, when a lid of the porcelain ball mill was opened, a gas within the ball mill blew up. At the same time, there was a very strong odor of ammonia, and a pH test paper wetted with water showed that the gas evolved in the ball mill were basic, that is, there was ammonia gas.
• the resultant flame retardant powder was passed through a 200-mesh standard sieve (JIS) to remove coarse particles having a size of 75 ⁇ m or more (1.0 % or less). The mean particle diameter was 15 ⁇ m, and no caking was observed.
• JIS 200-mesh standard sieve
• This flame retardant was used according to the formulations specified in Tables 2 to 6, and test pieces were molded therefrom in the same manner as that of Example 6. As a result, although molded articles in which the flame retardant was homogeneously dispersed could be prepared, they were colored. The results are given in Tables 2 to 6.
• a flame retardant powder was prepared in the same manner as that of Example 6, except that sodium stearate was used instead of aluminum tristearate. In this case, when a lid of the porcelain ball mill was opened, a gas within the ball mill blew up. At the same time, there was a very strong odor of ammonia, and a pH test paper wetted with water showed that the gas evolved in the ball mill were basic, that is, there was ammonia gas.
• the resultant flame retardant powder was passed through a 200-mesh standard sieve (JIS) to remove coarse particles having a size of 75 ⁇ m or more (1.0 % or less). The mean particle diameter was 12 ⁇ m, and no caking was observed.
• JIS 200-mesh standard sieve
• This flame retardant was used according to the formulations specified in Tables 2 to 6, and test pieces were molded therefrom in the same manner as that of Example 6. As a result, although molded articles in which the flame retardant was homogeneously dispersed could be prepared, they were colored. The results are given in Tables 2 to 6.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Inorganic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Fireproofing Substances (AREA)

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Citations (3)

• 1991
  • 1991-10-04 JP JP25784691A patent/JPH0772272B2/ja not_active Expired - Fee Related
• 1992
  • 1992-09-30 EP EP19920116754 patent/EP0535642B1/fr not_active Expired - Lifetime
  • 1992-09-30 DE DE1992606376 patent/DE69206376T2/de not_active Expired - Fee Related

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